Expansible rotary drill bit



June 3, 1952 A. w. KAMMERER EXPANSIBLE ROTARY DRILL BIT Filed Feb. 9, 1951 I N VEN TOR. AEcA/EE W EA MMEQEB A7 TOQNE V- Patented June 3, 1952 UNITED STATES PATENT OFFICE 2,599,060 EXPANSIBLE ROTARY DRILL B l! Archer W. Kammerer, Fullerton, Calif. Application February 9, 1951, Serial No. 210339 9 Claims. 1

This invention relates to drill bits, and more particularly to drill bits of the expansible type for drilling or reaming holes below well casing greater in diameter than the inside diameter of the casing through which the bit is capable of passing.

An object of the present invention 15 to provide an improved retaining device for maintain nga mandrel 'in appropriate telescopic relation Wlthln the main body of an expansible rotary drill bit.

Another object of the invention is to provide a retaining device for maintaining a mandrel in appropriate telescopic relation within the-main body of an expansible rotary drill bit, which device enables the mandrel to be assembled and disassembled with respect to the bit body at a substantial savings in time and at a greatly reduced cost.

A further object of the invention is to provide a retaining device in a drill bit of the aforenoted character that is capable of transmitting safely high loads between the mandrel and the bit body.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and form ing part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal section through a drill bit, with parts shown in retracted position for lowering through the well bore;

Fig. 2 is an enlarged cross-section taken along the line 2-2 on Fig. l;

Fig. 3 is a fragmentary longitudinal section, on an enlarged scale, through the mandrel locking portion'of the drill bit; I

Fig. 4is a cross-section taken along the line 4 -4 on Fig. 1.

The rotary drill bit A disclosed in the drawings is of the general type disclosed in United States Patent No. 2,466,991. It is attachable to astring of drill pipe B for lowering through a well casing C in a well bore D to a point below the casing shoe E at which enlargement of the well bore is to commence. The drill bit mayliave a pilot bit at its lower end for centering the tool in hole that may have already been drilled, or for drilling the central portion of new hole,

2 in the absence of a pre-existing hole. The main portion of the bit is capable of enlarging the'bore hole by producing and operating upon a forn'ia' tion shoulder (not shown), as fully described in the above referred to patent. v

The upper end of the bit consists of a driving mandrel ll having an upper pin l2 thread e'dly connected to a sub [3 forming the lower end of the string of drill pipe B. This mandrel-includes an upper kelly or drill stem member [4 telescoped within and slidably splined to the main 'bo'dy'l's of the bit. As disclosed in the drawings, the slidable splined arrangement may be provided [4a of the kelly hexagonal by forming the exterior in shape, and having such portion of the kelly telescopically received in a companion hexagonal socket l5a within the body I 5, disposed below a counterbore 16 in the body extending to its upper end.

The mandrel H has a limited range of longitudinal movement within the body I 5, its upward movement being limited by engagement of an external shoulder I7 on the kelly, positioned withi the counterbore l 6, with a retaining ring or sleeve I8 disposed within the counterbore l6 and releasably secured to the body l5, in a manner, hereinafter described.

The body I 5 has a plurality of e'xpansible parts mounted upon it, comprising cutter supporting members l9 pivotally mounted in a body slot '20 on pivot or hinge pins 2| suitably secured to the body. Each cutter supporting member I9 consists of a depending leg 22, having a bearing supporting pin 23 inclined inward ly and downwardly, and on which a roller side cutter 24 is mounted through the agency of roller and ball bearing elements 25, 26 that may be disposed between the bearing pin 23 and cutter 24 in any suitable manner. Each cutter supporting member also includes an upwardly extending arm 21 against which an elastic expander 26 bears. This expander is in the form of a compressed helical spring received within a socket 29 in the body and exerting its'force against the arm 21; so as to tend to swing it inwardly and thus urge the cutter 24, on the other side of the fulcrum pin 2 I, in an outward direction. The extent of such outward movement may be limited by engagement of stop shoulders 30 on opposite sides of the cutter supporting members I!) with cooperable body stop shoulders 3|.

After the cutters 24 have been expanded outwardly by the expander springs 28 to the maxi} mum extent, they can be locked in this position by a tubular member 32 of the mandrel I I, which is piloted in the kelly l4 and suitably secured thereto against relative longitudinal movement by a lower shoulder 33 abutting a companion shoulder 34 on the kelly and an upper nut 35 threaded on the upper end of the tubular member 32 and bearing upon an upper shoulder 36 on the kelly. The tubular member 32 is provided with a lock portion 31 that can be moved from an upper position in transverse alignment with inner supporting member recesses 38, which allow the cutters 24 to be retracted, to a lower position opposite lugs 39 formed on and projecting inwardly from the supporting member legs 22, which prevent retraction of the cutters, as explained in the patent above referred to.

The mandrel II is normally held in its upper position with respect to the main body I of the bit and supporting members [9 by a helical retractor spring 40 encircling the tubular member 32, with its upper end engaging the mandrel shoulder or flange 33 and its lower end engaging a spring seat and guide 4| at the lower end of the hexagonal body socket a. This spring seat 4| also serves as an upper bearing guide for the tubular member 32.

Circulating fluid can pass downwardly through the string of drill pipe B and through the tubular mandrel 32 for ejection from its lower discharge nozzle 42 onto the cutters 24, to cleanse them of cuttings and flush the latter from the drillin area to the top of the well bore. This circulating fluid is also availed of to unlatch the cutter supporting members l9, which may be held initially in retracted position in a positive manner.

The device for securing the cutter supporting members [9 positively in retracted position includes a hook 43 secured to the inner portion of each member IS, the ends of which are received in holes 44 in a strip 45 extending across the mandrel outlet 42. The drill bit, after having been lowered in retracted position to the point at which the reaming operation is to begin, may be released for operation by starting the pumps at the surface of the well bore, which will force fluid down through the drill string B and mandrel 32, causing it to impinge upon the latch strip 45, blowing or forcing the latter off the ends of the hooks 43, to permit the spring expanders 28 to shift the cutter supporting arms 2'! inwardly and the cutters 24 outwardly against the formation.

In the operation of the device, the drill bit A is mounted on the lower end of the drill string B, with its parts held in retracted position by the latch strip 45. The mandrel ll then occupies an upper position, illustrated in Fig. l, in which the Kelly shoulder I1 is adjacent the retainer sleeve I8, and with the lock portion 31 elevated above the lugs 39 on the cutter supporting members l9, being received within the inner recesses 38 in the latter. The tool is lowered through the well casing C, and, upon reaching the position in the well bore below the casing shoe E at which the drilling operation is to begin, the pumps are started at the top of the well bore, causing fluid to impinge on the latch strip 45, forcing it bydraulically off the hooks 43 and releasing the cutter supporting members IQ for outward expansion under the influence of the springs 28.

The drill string B is then rotated, to rotate the main bit body 15 through the splined kelly and body connection 14a, l5a, the expander springs 28 forcing the arms 21 inwardly and the cutters 24 outwardly against the formation. Rotation is continued. without movin the drill string B longitudinally, until the side cutters 24 enlarge the diameter of the hole to the maximum extent, as determined by the eventual abutting of the supporting member stop shoulders 30 with the companion body stop shoulders 3|. When such abutting occurs, a formation shoulder will have been formed in the well bore D upon which the cutters 24 can rest, in order to support the latter and the body [5 and resist their downward movement.

Inasmuch as the body l5 cannot move downwardly, drilling weight imposed on the drilling string B shifts its connected mandrel ll downwardly within the body against the action of the retractor spring 49 until the lower end of the kelly l4 engages the spring seat and guide 41. During this downward movement, the Kelly shoulder i1 is free to move downwardly within the body counterbore H5- away from the retaining sleeve l8. Such downward movement also shifts the tubular member 32 downwardly to position the lock portion 31 opposite and in alignment with the supporting member lugs 39, providing a positive lock that prevents inward movement of the cutters 24. So long as down weight is imposed on the drill string B, and the cutters 24 rest on the formation shoulder, the cutters are prevented from moving inwardly by engagement of their lugs 39 with the mandrel lock portion 31, which precludes the drilling of an undergauged hole.

Drilling is continued by rotating the drill bit A to ream the hole D in a downward direction to the desired extent. When the drill bit is to be retracted and removed to the top of the Well bore, the drill string B is elevated, which moves the side cutters 24 above the formation shoulder and permits the retractor spring to shift the body 15 downwardly to the extent determined by engagement of the retainer sleeve [8 with the external Kelly shoulder IT. This action repositions the mandrel lock portion 3'! opposite the supporting member recesses 38 and above their lugs 39, allowing the cutters 24 and their supporting members IE to swing inwardly when the tool passes back into the casing C upon elevation of the drill string B. The cutters and their supporting members will ride the wall of the casing during elevation of the string until the tool is re-, moved from the top of the well bore. The force required to elevate the tool is transmitted in an upward direction from the Kelly shoulder I! to the retaining ring or sleeve [8, and from the latter to the body l5 of the tool, through a retaining sleeve lock device now to be described.

The retaining sleeve I8 is piloted within the upper end of the main body !5 of the bit and has an external toroidal race 41 disposed opposite a companion toroidal race 48 in the bit body. Locking balls 49 are disposed circumferentially around the sleeve l8 and body I5, each ball being engageable with each race 47, 48. These balls are insertable between the races, and are removable therefrom, through a transverse hole 50 in the body extending into the body race 48. Removal of the balls 49 from the races 47, 48 may be prevented by a suitable plug 5| threaded into the hole 50. Inadvertent unscrewing of the plug 5| may be prevented in any suitable manner, as by producing indentations in the periphery of the plug 5| and adjacent body by a center punch.

The retaining sleeve I8 has its lower end spaced from the bottom of the counterbore l6 a sufficient extent to allow the mandrel H to move longitudinally with respect to the main body l5 of tbs b t erthe m r 9 a rpr'i fiii' rd 'fi nalt e s. q i e el .Q weme l e h r abov th -su t n m er u s 'r a im nt berew mass ri de ve. T s ve i i-. 5 disp edebpveih Kelly sec re. i lower mdbe s eneeseable by t e r-fieward thrust is transmitted from the shoulder ll theate e1 and m the leve PQ iQ of the ;sleeve .race 4 ,1 through the ballets to the er D reen 9 t P r 8-. .le smue as a large number of balls 49 can be disposed e m ent elly e ce 41, .8, he .q b n eesit n m t n t n t iS vvery at. b e greaterthan the maximum force to which the ant s ms a d t e, drill bi ma be, ub-- ieste the. drill i be om s c ni he b le;- e di b epm n s e iq ia p w is lif urea-At the -.1 a c y n it sleeve 18 and int vening balls 49 sme e h n mple teet au mi s e t mum. jarring f e that might be required. When the mandrel .l l is disposeddn a downward position within the ma inbodywof the bit, as during the perform; aneeof a h ole enlarging operation, there is no material force imposed on the sleeve I8. However, the balls 49 still prevent the sleeve [8 from dropping downwardly within the'body i5, retaining it in its appropriate assembled position within the latter.

The sleeve and ball arrangement facilitates assembly and disassembly of the driving mandrel H within the bit body L5. Thus,.with the sleeve i8 and balls 49 removed, the driving mandrel II is telescoped within the body; whereupon, the sleeve l8 may be slipped over the upper end of the kelly IA and above the flange I! of the latter, being inserted in the upper end of the kit body counterbore 16 until the sleeve race 41 is opposite the body race 48. The required number of balls 49 may now be placed through the body hole 50 and in the races; whereupon, the plug Si is threaded into the hole, to prevent the balls 49 from leaving the races 41, 48. As mentioned above, a center punch may be used to form a metallic lock between the plug 5| and body i5 by deforming the outer margin of the plug.

The mandrel II is now held in appropriate position within the main body i5 of the bit, the sleeve and ball lock 41, 48, 49 preventing its removal from the latter. In addition, the sleeve and ball lock are capable of transmitting exceedingly high loads between the mandrel I I and the body I 5 of the tool. After the hole enlarging operation has been completed and the tool removed to the top of the well bore, the insertion of a suitable wrench (not shown) in a non-circular socket 5la in the screw plug 5| will allow the latter to be unthreaded from the hole 58; whereupon, the balls 49 can be removed through the open hole, the sleeve It slipped off the upper pin end of the driving mandrel H, and the latter removed from the main body of the bit. The parts may be reassembled again, when desired, by re-telescoping the mandrel H in the body l5, placing the retaining sleeve or ring [8 over the kelly i4 and in the counterbore i6, reinserting the balls 49 through the body hole 50, and closing the latter with the plug 5|. It is evident that all of the locking parts !8, 49, 5| can be used repeatedly, since there is no material wear on the latter. It is also evident that the assembly of the mandrel II in the body l5, and its disassembly therefrom, can be effected very easily and in a minimum of time.

Theifiveritor claims: 1. an expansible rotary well drilling bit: ui,.bo'dy; cutter means mounted on said body for a eral outward movement with re- Sheet to said body; means for expanding and ding said cutter. means laterally outwardly of aid. body, said expanding and holding means includirig. a mandrel telescoped and movable m ntiidiriauy within said body; an annular member piloted in said body to prevent withdrayval of said mandrel from said body; and reliable element's" engageable with said annular member and body toprevent removal of said annular member fromsaid body.

,2,., In an expansiblerotary well drilling bit: a ma nbo wi te mean mou .on sa d body Iimriatera uive s inev men i r pe to se dt dr; .mee sIQ e ndi o in d cutt rwsans l t l utwa dl a ,be ysaid es -endin a .hOlding mea s nc d ie 'a mandrel telescoped andmovable longitudinally within said body a sleeve disposed around said mandrel and piloted in said body to prevent withdrawal i .said mandrel from said body; said sleeve and body having opposed races; and rollable, elements on said races to prevent relative longitudinal movement in at least one direction between said sleeve and body. i

,S In an expansible rotary well drilling bit: amain body; cutter means mounted on said body ior, lateral outward movement with respect to saidbody; means for expanding and holding said cutter rneanslaterallyoutwardly of said body, said expanding and holding means including a mandrel telescoped and movable longitudinally within said body; a sleeve disposed around said mandrel and piloted in said body to prevent withdrawal of said mandrel from said body; said sleeve and body having opposed toroidal races: and balls in said races to prevent relative longitudinal movement in at least one direction be tween said sleeve and body.

4. In an expansible rotary well drilling bit: a main body; cutter means mounted on said body for lateral outward movement with respect to said body; means for expanding and holding said cutter means laterally outwardly of said body, said expanding and holding means including a mandrel telescoped and movable longitudinally within said body; an annular member engageable with said mandrel to prevent withdrawal of said mandrel from said body; said annular member and body being telescoped one within the other; and rollable elements engageable with said annular member and body to prevent removal of said annular member from said body.

5. In an expansible rotary well drilling bit: a main body; cutter means mounted on said body for lateral outward movement with respect to said body; means for expanding and holding said cutter means laterally outwardly of said body, said expanding and holding means including a mandrel telescoped and movable longitudinally within said body; a sleeve disposed around said mandrel and engageable with said mandrel to prevent withdrawal of said mandrel from said body; said sleeve and body being telescoped one within the other; said sleeve and body having opposed races; and reliable elements in said races to prevent relative longitudinal movement in at least one direction between said sleeve and body.

6. In an expansible rotary well drilling bit: a main body; cutter means mounted on said body for lateral outward movement with respect to said body; means for expanding and holding said cutter means laterally outwardly of said body, said expanding and holding means including a mandrel telescoped and movable longitudinally within said body; a sleeve disposed around said mandrel and engageable with said mandrel to prevent withdrawal of said mandrel from said body; said sleeve and body being telescoped one within the other; said sleeve and body having opposed toroidal races; and balls in said races to prevent longitudinal movement in at least one direction between said sleeve and body.

7. In an expansible rotary well drilling bit: amain body; cutter means mounted on said body for lateral outward movement with respect to said body; means for expanding and holding said cutter means laterally outwardly of said body, said expanding and holding means including a mandrel telescoped within and slidably splined to said body, said mandrel having means thereon adapted for connection to a drill string to move said mandrel longitudinally in said body, said mandrel having a flange disposed in said body; a sleeve disposed around said mandrel and piloted in said body above said flange to limit upward movement of said mandrel relative to said body; and rollable elements engageable with said sleeve and body to prevent removal of said sleeve from said body.

8. In an expansible rotary well drilling bit: a main body; cutter means mounted on said body for lateral outward movement with respect to said body; means for expanding and holding said cutter means laterally outwardly of said body, said expanding and holding means including a 8 mandrel telescoped within and slidably splined to said body, said mandrel havingmeans thereon adapted for connection to a drill string to move said mandrel longitudinally in said body. said mandrel having a flange disposed in said body; a sleeve disposed around said mandrel and piloted in said body above said flange to limit upward movement of said mandrel relative to said body; said sleeve and body having opposed toroidal races: and balls in said races to prevent relative longitudinal movement in at least one direction between said sleeve and body.

9. In an expansible rotary well drilling bit: a main body; cutter means mounted on said body for lateral outward movement with respect to said body; means for expanding and holding said cutter means laterally outwardly of said body, said expanding and holding means including a mandrel telescoped within and slidably splined to said body, said mandrel having means thereon adapted for connection to a drill string to move said mandrel longitudinally in said body, said mandrel having a flange disposed in said body; a sleeve above said flange and disposed around said mandrel to limit upward movement of said mandrel relative to said body; said sleeve and body being piloted one within the other; and rollable elements engageable with said sleeve and body to prevent removal of said sleeve from said body.

ARCHER W. KAMMERER.

No references cited. 

